Piston for internal-combustion engines.



1. T, BENTHAL'L. BISTON FOR INTERNAL-COMBUSTION ENGINES. APPLICATION FILED FEB. 25, l9l6.

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WWWWWWW wwwwwww farro/mms' liti JESSE THOMAS BENTHALL, 0l? SUFJFOLK, VRGINId..

PISTON FR NTERNAL-CVIBUSTION ENGINES.

Application led February 25, 1916. Serial No. 80,507.

To all whom t mag/concern:

Be it known that l, JESSE T. BnNri-IALL, a citizen of the United States, and a resident of Su'olk, in the county of Nanselnond and State.of Virginia, have invented a certain new and useful Improvement in Pistons Jfor Internal-Combustion Engines, of lwhich the following is a specification.

My invention relates to improvements in internal combustion engines, and it consists `in the combinations, constructions, and arrangementshereln descrlbed and claimed.

An object of my invention is to provide an improved piston for an4 internal combustion engine whereby an increase of power is obtained.

Ai further object of my invention is to provide an internal combustion engine having a piston capable of delivering more of the power of'the explosive charge 'than a piston constructed in the ordinary manner,

whilel at the same time not exceeding the ordinary piston in cost.

Other objects and advantages will appear in the following specication, and the novel features of the invention will be particularly pointed out in the appended claim. 4

My invention is illustrated in the accompanying drawings forming part of this application, in which- Figure 1 is a sectional view through an engiile and piston, constructed according to my invention, and

Fig. 2 is an enlarged sectional View through a portion of the device.

In carrying out my invention l may make use of a cylinder of any conventional form. lin Fig. l I have shown such a cylinder 'l provided with an outer wall 2, the space 3 between the inner and outer walls being for the ordinary water jacket.

lin the present instance, I have shown the piston as comprising a head portion 4 which forms the integral end of a cylinder 5.' 'lhe piston has inwardly projecting lugs 6 which are bored as shown at 7 to receive a wrist pin 8. 'lhe pitman 9 has a portion l() provided with a bearing l1 which surrounds the 'central portion of the wrist pin, and thus 'connects the piston to the pitlnan or connecting rod. l

llt will be observed that the outer surface ofthe head 4 is ilat or plane, as shown at 4, while at 4b there is a forwardly extending Hangehaving a concave curved portion 4c on that side of the ange facing the plane surface 4a.

The construction described provides a pis-4 ton having a hea the greater portion of which is a plain flat surface,l with outwardly curved edges, the `curved portions being relatively near to 'the sides of the' piston.

It is obviously desirableto concentrate as much as'possible of the thrust of the exploding charge directly against the pistonI head. By constructing a piston in the manner described herein, the force of the explosion along the side walls is deflected away from the point of escape around the piston head and Jfocused directly upon the piston head, thereby reducing the leakage around it.

Now I have found by actual experiment that a piston constructed in the manner described gives considerably more power than one which has merely a dat surface or a plane surface for the piston head.

l am wellaware that the so-ealled dishing of the piston head is not new, and l do not claim such broadly; but l have found, by actual experiment, that a piston constructed in the manner described also gives more power than one with a dished or concaved head, which advantage in erlormance ll conoci to result from the lidllowing causes, to wit: that in the case of the dat surface, the torce of the explosion is exerted in straight lines, as between the iston head and the cylinder head, along tie entire diameter ot the piston head, while in the case of the dished or concaved head, the

'force is partially deflected as between the piston head and the cylinder head, and to some extent expended in circumferential directions indirectly, therehy dissipating a iet oi' heat which is attained by melting the' main body portion of the head. Het vorplane.

llt the same time, ll attain the advantage of p 'the dished piston by forming the curved.

lill' portion at the very place where it is needed, to wit, toward the edge of the piston, this curved portion being entirely suliicient to accomplish the results of the ordinary dished piston without, however, causing an extra amountJ of surface, which would, therefore, absorb more heat. In actual practice I have tried out pistons with plane surfaces, and those with the so-called dished Surfaces, that is to say, with a recess of convex cross section extending substantially over the whole of the end of the piston. In each instance I have found that the engine under the same conditionsgives less power than when the piston is constructed in accordance with my invention.

It will be seen at once that I have accomplished a new result without increasing the cost of the piston. The piston head may be cast to a shape approximating that of the pistonwhen finished, and a finishing tool maybe run over the cast head so as to give the nish required.

The piston is provided with the usual packing rings 12. In this connection I wish to mention also that, a piston constructed in accordance with my invention tends to prevent, to a certain extent, the forcin of the products of combustion past the si e walls of the piston. The deposit of carbon upon the side walls is, therefore, eliminated to a certain extent, while at the same time the advantages of the Hat piston head are also retained.

The relatively narrow iange, 4b, is a continuous and unbroken circle and projects a relatively short distance beyond the Hat surface, 4a, and the inner concave surface of the flange as shown at 4, extends on a continuous concave line from the upper edge of the flange to the base, where it merges into the flat surface, 4a. By thus forming the flange, a strong and rigid continnation of the effective surface of the piston is provided, which is not liable to undue expansion, and thus the increase of frictional contact between the outer surface of thelange and the wall of the chamber is.

obviated,

I claimz- A piston for internal combustion engines, having a iiat surface facing the combustion chamber, and a relatively narrow continuous integral rigid flange surrounding the fiat surface and projecting therefrom at the outer edge, the inner surface of said ange formed on a continuous concave curve beginning at its upper edge and merging at its base into the fiat surface, whereby the currents of the expanding and eddying ases are directed by such inner curved surace away from the space between the piston and cylinder wall.

JESSE THOMAS BENTHALL. 

